Positioning remote contact or non-contact sensors to make various measurements and transmitting the measured values, such as light, voltage, current, temperature, sound, motion or continuity, to a receiving unit is known in the patent literature. Remote clamp meter positioned apart from a display unit is also known. Conversely, a removable display for a multi-meter base unit is also known.
Remote, transmitting sensors have also been used in surveying electrical power lines, fluid conduits or machineries. Examples in the electrical power line art include U.S. Pat. No. 5,426,360 to Maraio et al., U.S. Pat. No. 7,715,176 to Perez et al., U.S. Pat. No. 5,565,783 to Lau and U.S. published patent application no. 2002/0075616 to Montjean. Examples in the fluid conduit art include U.S. Pat. No. 7,725,270 to Davis and U.S. Pat. No. 7,526,966 to Gysling et al. Examples in fault detection field for machineries include U.S. published patent application 2004/0019461 to Bouse et al. and U.S. Pat. No. 6,078,874 to Piety et al. Other examples of remote ultrasonic sensors include U.S. Pat. Nos. 6,220,098 to Johnson et al. and 6,189,384 to Piety et al.
However, the prior art lacks a system's approach to collecting data or measurements from remote sensors. For some of the prior art references discussed above, the base units or main units do not have a way to distinguish signals from one sensor from another. Furthermore, the devices of the prior art do not show the ability for the remote sensors to be attached to the main unit to become a single integral hand-held unit and to be used as such.